Percussion fuse



April 16, 1946. Q RASMUSSEN @398,718

PERCUSS ION FUSE Filed Deo. 7. 1942 /a [sa Hl WQRNEYS Patented Apr. 16, 1946 PERCUSSION FUSE (Blaf Rasmussen, Dayton, Ohio,- assignor to. General Motors Corporation, Detroit, vMich., a corporation of Delaware Application December 7, 1942,y Serial No. 468,032

'7 Claims.

This invention relates to improvements in percussion fuses particularly adapted to be used to nre and explode land mines.

It is among the objects of the present invention to provide a percussion fuse of simple structure and design which is adapted to re a land mine only in response to the application of a predetermined load thus eliminating the eX- plosion of the mine accidentally or by the application of loads below the predetermined value.

A further object of the present invention is to provide a percussion fuse which cannot be detected by the usual electro-magnetic detecting devices.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a plan View of one form of the present invention.

Fig. 2 is a sectional View taken along the line 2-2 of Fig. 1.

Fig. 3 is a plan view of a modified form of the present invention, and

Fig. 4 is a sectional view taken alongr the line 4-4 of Fig. 3.

Referring to the drawing and more particularly to the Figs. 1 and 2 thereof, the numeral 2B designates the dish-shaped base portion of the percussion fuse box. This may be made of any suitable non-metallic material but for large quantity production purposes a moldable plastic such as Bakelite or the like is preferable inasmuch as no finishing processes are necessary after the piece is taken from the mold. The base is provided with a knob-like extension 2| having a central passage 22 both ends of which open into larger recesses in the Wall of the base. Recess 23 is at the inner end of passage 22 and the recess at the outer end of said passage re ceives the non-metal tube 33 containing the primer charge 3 I.

The firing pin 25, made of any suitable nonmetallic material such as a plastic, ceramic o1' glass comprises a comparatively strong body portion 23 which slidably ts into the passage 22 and a thin, integral, frangible flange 28 which normally rest upon the inner surface of the base Wall about said passage. The inner end of the body portion 25 of the firing pin is pointed and normally spaced from the primer charge as shown in Figs. 2 and 4.

gg outer surface of the cover.

opening `ll which is suspended between `two opposite walls 33 and 34 of the dish-shaped base portion 20. Any hardwood maybe used to make a satisfactory, substantially stili reed. One end of the reed has an opening which -ts over the nipple 35 on the base portion 20 thereby securing this end of the reed to the base. The opposite end of the reed merely rests upon the upper surface of the base wall 30 so that a wooden striker block 35 attached to the reed, normally is directly above the ring pin and spaced therefrom.

The casing of the percussion fuse has a lid or cover 40 tting into a peripheral recess provided on the base 20. This cover 4|] may be secured to the Ybase by cementing or any other similar manner as long as no metal posts are used as fasteners. A passage or opening 4| is provided in the cover for slidably receiving the piston plug 42 the outer end of which extends beyond the Piston plug 42 isheld suspended in the cover opening 4| by a frangible, annular ange 43 formed integral with the piston plug and resting in an annular recess provided in the outer surface of the cover surrounding A depending projection 41 on the piston plug 42 normally engages the reed 33 near its end anchored to the nipple 35 of the base 20.

Like the cover and base, the piston plug 42 is made of non-metallic material.

In the Figs. 3 and 4, a modified form of the invention is illustrated. The base portion |28 of the percussion fuse box is somewhat like the base portion 2U shown in Fig. 2. It has a knob like extension |2| in which a ring pin |25, identical vwith firing pin 25, is carried. This ring pin |25 has a fran-gible flange |28. A primer charge |3|, inl container tube |30 is 1ocated in alignment with ring pin |25 so that it may be fired by said pin. A reed |32 anchored at one end to the nipple |35 on the base has its other end resting upon the wall |33 of said base. This reed |32 has a striker block |35 normallyspacedfrom and positioned directly above the ring pin |25.

The cover. or lid |40 ol.V the modified form of percussion fuse differs, however, from the lid 4|) ofthe device shown inFig. 2. This cover |45 is a single piece having a peripheral recessed flange 14| tting upon and secured to the peripheral edge of the base |20. Cover |45 has two inwardly extending lugs |42 and |41. The lug |42 has a rounded end which hingedly nts into a socket like indent,` |43 in the upper surface of the base wall |33. The lug |41 normally Numeral 32 designates a non-metallic reed 55 rests upon the reed |32 adjacent its anchored end. The portion of the cover between lugs |42 and |41 is substantially thick to provide strength and rigidity while on the contrary a peripheral area. designated by the numeral |44 is of a comparatively thinner. construction so as to provide a frangible area in the cover which is suiciently strong to support a certain load but which will fracture in response to a predetermined load in excess of said certain load applied to the Ypercussion fuse boX.

Like the percussion fuse of Fig. 2, the modied form of Figs. 3 and 4 has its base and cover made of non-metallic material, preferably a moldable plastic, its firing pin of glass and its reed of a hard wood. No metal whatsoever is used in any part of the device. The vpurpose of this is to eliminate the possibility of its detection by any type of electrical detector adapted to indicate the presence of a metal.

When the percussion fuse is in operative c onnection with a mine, particularly a land mme,

the fuse itself is buried close under the surface of the ground so that any loads passing-over it is applied to the cover of the percussion fuse. The piston-plug 4E or the cover |40 may have their frangible portions so designed and constructed as to be able safely to support any chosen load without fracturing. For instance these members 412 and may have their frangible areas or sections 43 and |44 respectively so thick as to support a load of 600 pounds without fracturing.

However if a load in excess of 600 pounds would be applied to said members their frangible sections 43 and |44 respectively would fracture.

When the section 43 of the piston-plug 42 fracn tures in response to the application of a certain i load, the piston-plug 42 is forced downwardly through passage 4i and thus lugr or projection 4l presses upon and flexes the reed 32 downwardly. As the stiff reed 32 is bowed or flexed downwardly energy is built up therein which is suddenly reapplied to cover |49 fractures its frangible sec i' tion |44 and moves the thicker part thereof downwardly said part pivoting about the lug |42 resting in the socket |43 of wall portion |33. Lug |41 0f the cover bows reed |32 which, when it passes the ledge of wall |33 thrusts striker block |36 against the firing pin |25, -breaking its flange |28 and urgingthe pin |25 into firing, engagement with the primer charge |30. .It will be noted that the design and construction of thetwo forms of percussion fuses illustrated precludes the entrance of dust and dirt into the interior thereof inasmuch as the two parts of the container, that is,.the base and cover, are sealed together. This provides for a safe and positively acting percussion fuse. Either device may easily ybe arranged for ,any selected load at which the mineis `tibe exploded. For a heavier load a piston plug with a heavier flange 43 Vis placed in the cover opening 4 |v and in the other structure a cover having a heavier frangible section |44 is placed on the base portion |20 and sealingly secured thereto.

When buried in the groundy so that the percussion fuse is just beneath the surface, no way of detecting its presence excepting perhaps by the hit Vor miss probing method is possible. The use of an electromagnetic detector is futile for neither the percussion fuse nor mine has any metal part that would be indicated by such a detector.

The design and construction of the two forms of devices is simple for one consists of five parts four of which may be molded, the other consists of four parts three of which are shown as molded construction.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, itis to be understood that other forms might be adopted, all coming within the scope 0f the claims which follow.

What is claimed is as follows:

1. A completely non-metallic percussion fuse comprising in combination, a non-metal container a portion of which is frangible under a predetermined load; a non-metal firing pin in said container provided with a fragile portion whichr holds said pin in normal position; and a non-metal, stiff reed suspended within the container and adapted to be flexedk and released to fracture the fragile portion of the firing pin and actuate said pin in response to fracture of the container portion by the application of said load,

' 2. A complete non-metallic percussion fuse comprising in combination, a plastic container having a portion frangible under a predetermined load; a glass firing pin in said container, said pin. having a thin flange holding the pin in normal position in said container; anda stiff, wood reed suspended within the container and adapted to bevflexed to strike the ringpin, break its flange and quickly thrust said pin outwardly from .said container in response to fracture of the frangible container portion.

3. A percussion fuse comprising in combina-- tion, a non-metal housing provided with an opening in its one wall; a non-metal firing pin in said opening, said pin having a frangible flange engaging the housing to support the ring pin; a non-metal reed supported only `at its'ends in the housing, one endbeing anchored to the Ahous-V ing; and a non-metal cover for the housing, said cover having an area of reduced thickness adapted to be fractured in response to a predetermined load being applied upon the cover and cause movement of the cover toward the housing, said cover having a lug normally engaging the reed.

ll. A percussion fuse comprising in combination, a non-metal box including a main body portion and a cover having aV portion frangible at a predetermined applied load; a non-metal firing pin slidable fitting in an opening in said body porti-on, said pin having a frangible flange holding the pin in normal position; a non-rnetalreed suspended only between two opposite walls of the body portion, one end of the reed being anchored to the one body porti-on wall; and moans on the cover, normally engaging the reed and adapted to flex the'reed and thereby diseugage its one end from the body portion wall whereby said reed will strike the ring pin Vand fracture its flange to thrust the ,firing pin outwardly' through thebodyportion asA the cover 'is fractured by the application of said predetermined load. s '75. A percussion fuse comprising in combination, a non-metal housing consisting of a base and a frangible cover; afiring pin of non-metallic material slidably heldin a passage in a wall of the base said pin having a frangible flange normally holding the pin within,l said passage; a non-metal, stiff reed suspended only at` its ends between two walls of the base, so that one end of the reed lies above and is spaced from the ring pin, the other end of said reed being anchored to its base wall; a lip on said cover, hingedly engaging the base providing a pivot member about which the cover moves relatively to the base when said cover is fractured by the application of a predetermined load; and a depending lug on said cover normally engaging the reed and adapted to flex said reed to causeV it to strike the firing pin and fracture its flange as said pin is thrust outwardly through the passage in the base in response to fracture of said cover and its movement toward the base.

6. A completely non-metallic percussiontfuse comprising in combination, a box of plasticvraterial consisting of a base portion and a cover,

a portion of which is frangible when a predetermined load is placed on said cover; a rglass firing pin slidably supported Within a passagegin one wall of the base portion, said firing pin having a comparatively thin, fragile flange by which the pinis held in normal position within said passage; a reed of comparatively hard but resilient wood suspended by its two ends in the base portion, one end directly over the firing pin and spaced therefrom; and means on the cover normally engaging the reed and adapted to flex it for striking the pin, fracturing its flange and thrusting it outwardly through the passage when the cover is fractured by said load.

'7. A percussion fuse comprising in combination, a non-metallic container consisting of a base and a lid, each of which is provided with a passage; a non-metallic firing pin in the passage of the base, said pin having a frangible flange normally holding the pin within the passage of the base; a non-metallic, substantially stiff reed suspended in the base, one end of Said reed being anchored to a Wall of the base, the other end resting on the opposite wall of the base and directly above the firing pin; and a nonmetallic plug slidably fitting in the passage of the lid and having a frangible annular rim engaging the lid to hold the plug in said passage, said plug having a depending lug normally engaging the reed and adapted to flex said reed and thrust it against the firing pin to break its flange and quickly push said iiring pin outwardly in its passage as the rim of the plug is fractured and the plug is pushed downwardly into the lid.

OLAF RASMUSSEN. 

